From 608532dfcde97a984ed10ad60a01e0210be65d0d Mon Sep 17 00:00:00 2001
From: Étienne Loks <etienne.loks@iggdrasil.net>
Date: Mon, 16 Jan 2023 16:43:21 +0100
Subject: GeoVectorData: method to update from a geojson

---
 ishtar_common/models_common.py | 49 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

(limited to 'ishtar_common/models_common.py')

diff --git a/ishtar_common/models_common.py b/ishtar_common/models_common.py
index 151ab5650..a6f9ac0e8 100644
--- a/ishtar_common/models_common.py
+++ b/ishtar_common/models_common.py
@@ -8,6 +8,7 @@ Generic models and tools for models
 import copy
 from collections import OrderedDict
 import datetime
+import fiona
 import json
 import logging
 import os
@@ -25,7 +26,7 @@ from django.contrib.contenttypes.models import ContentType
 from django.contrib.contenttypes.fields import GenericForeignKey
 from django.db import migrations as db_migrations
 from django.contrib.gis.db import models
-from django.contrib.gis.geos import Point
+from django.contrib.gis.geos import GEOSGeometry, Point
 from django.contrib.gis.gdal.error import GDALException
 from django.contrib.postgres.fields import JSONField
 from django.contrib.postgres.search import SearchVectorField, SearchVector
@@ -2117,6 +2118,17 @@ GEOMETRY_TYPE_LBL = {
 }
 
 
+GEOTYPE_TO_GEOVECTOR = {
+    # key: (geom attr, need list convert)
+    "Point": ("point_2d", False),
+    "LineString": ("multi_line", True),
+    "Polygon": ("multi_polygon", True),
+    "MultiPoint": ("multi_points", False),
+    "MultiLineString": ("multi_line", False),
+    "MultiPolygon": ("multi_polygon", False),
+}
+
+
 class GeoVectorData(Imported, OwnPerms):
     SLUG = "geovectordata"
     RELATED_MODELS = [
@@ -2589,6 +2601,41 @@ class GeoVectorData(Imported, OwnPerms):
             return self._geojson_serialize("multi_polygon")
         return "{}"
 
+    def update_from_geojson(self, geojson: str, save=False) -> bool:
+        """
+        Update geometry from a geojson string
+        :param geojson: geojson
+        :param save: save the object if set to True
+        :return: True if update
+        """
+        if not geojson:  # no data provided
+            return False
+
+        with fiona.open(geojson) as src:
+            if len(src) != 1:
+                # ambiguous -> need only one feature
+                return False
+            feature = src[0]
+            geom = feature["geometry"]
+            if geom["type"] not in GEOTYPE_TO_GEOVECTOR:
+                # unknown geometry type
+                return False
+            feature_attr, need_list_convert = GEOTYPE_TO_GEOVECTOR[geom["type"]]
+            if need_list_convert:
+                geom["coordinates"] = [geom["coordinates"]]
+            geom = json.dumps(geom)
+            setattr(self, feature_attr, GEOSGeometry(geom))
+            if save:
+                self.save()
+            geo_attrs = ["point_2d", "point_3d", "x", "y", "z", "multi_line",
+                         "multi_points", "multi_polygon"]
+            geo_attrs.pop(geo_attrs.index(feature_attr))
+            for geo_attr in geo_attrs:
+                setattr(self, geo_attr, None)
+            if save:
+                self.save()
+        return True
+
     @classmethod
     def migrate_srid(cls, new_srid):
         fields = (
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